Anjem Choudary is an obnoxious individual with repugnant views that he has aired widely over the past few days since his followers demonstrated against British soldiers who had returned from Iraq. He has been quoted as saying he would like to see the “flag of Allah” fly over Downing Street and “a pure Islamic state with sharia law” established in Britain. All women, Muslim or non-Muslim, would have to wear a burqa; a woman’s evidence would be subordinate to a man’s in court; drunks would be whipped in public; and adulterers would be stoned to death.

He has described British troops as “cowards” and a tape recording has emerged of him telling his followers “you have money that can go towards the mujaheddin” – remarks that may have broken anti-terrorist legislation. Augmenting this unpleasant profile, former friends have come forward with photos and stories of his drunken roistering as a law student and he has acknowledged that he and his family live on state benefits.

Mr Choudary is also British. He was born and raised in Welling, southeast London. That forlorn suburb offers a lesson on how the rest of society should treat him. In the early 1990s “anti-Nazi” demonstrators flocked to Welling to protest outside the local headquarters of the British National party, where British citizens with views no less repugnant than Mr Choudary’s were building a political base among the local white population. The rule of law was upheld. Violent demonstrators were arrested and the BNP’s political rights were protected; but its headquarters was shut for breaching planning controls.

Since then Britain has suffered home-grown Islamic terrorism and has brought in laws to try to prevent its recurrence; but the principle remains the same. Mr Choudary is subject to the law. If he breaks it he should be punished, but if he does not he has every right to spout his absurd views. There have been calls to have him silenced. Our poll today suggests a majority would like to see him arrested on the grounds that he is dangerous.

This misses the point. The lesson of Guantanamo Bay and “extraordinary rendition” is that a free society gives ammunition to the enemy if it is provoked into a breach of its own revered principles, which means fighting on the higher moral ground. The best way of ensuring that his views get no more traction is to let him air them so they can be seen for being vacuous. Mr Choudary and his tiny coterie must not be turned into martyrs. Far better that we deploy the weapon for which Britain is famed: humour and ridicule. He is, to use a well-worn phrase, a sick joke and should be treated as one.